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Marcel Verdaasdonk
Netherlands
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Posts 3975
23 Jan 2012 12:18
| Why isn't there support for 1920*1200?
When there is 1920*1080 support on the natami?
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Istvan Szekeres
Hungary
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Posts 60
23 Jan 2012 15:39
| One more spare question... Why is this important?
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Andreas G. Szabo
Germany
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Posts 134
23 Jan 2012 17:39
| This is important because my monitor can 1920x1200.
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Marcel Verdaasdonk
Netherlands
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Posts 3975
23 Jan 2012 19:12
| +1
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Rune Stensland
Norway
| | (MX-Board Owner)
Posts 871
23 Jan 2012 19:25
| Every system has a limt(bandwidth) and the max res. Of the natami is not yet determined.with the aga chipset it was possible to open shires screens in overscan mode. The height of the display could become higher than 256(512). Shires at 8bpl had a cost. It was dma. The blitter and cpu was 2nd priority, since almost all dma was used to display the screen. Copyspeed fro
Fastram to chip was reduced to 1.8mb/s. This was too slow, so the shires 1280x256(512) mode was rarelly used.
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Marcel Verdaasdonk
Netherlands
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Posts 3975
23 Jan 2012 22:06
| Okay, i can understand the bandwidth requirements that are about 9% higher then 1080p.(120 more horizontal lines) In theory the Natami would have enough bandwidth for this resolution Taking a bit more then 1/3 of the total bandwidth available. Why request such a resolution?
Because it is now it can be still added without too much trouble.
Besides that i think that 1920*1080 will be used just as much as 1920*1200 which would be replied as rarely.
a sane resolution is small enough so one can still recognize the icons on screen.
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Jakob Eriksson
Sweden
| | (Moderator)
Posts 1097
23 Jan 2012 22:41
| "it is now it can be still added without too much trouble" No, I don't think so. It is not harder to add it in the future.
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Marcel Verdaasdonk
Netherlands
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Posts 3975
24 Jan 2012 05:37
| Thomas richer has recently been working on monitor drivers.
That i was refering to, it's fresh in memory.
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Rune Stensland
Norway
| | (MX-Board Owner)
Posts 871
24 Jan 2012 06:50
| A 32bit display (24bit truecolor) in your resolution will require fetching of 1920 * 1200 * 4 (9 216 000 bytes) per frame. I believe this is to much for the Natami.. However we have the HAM8 mode wich enables us to display a 18bit truecolor with much less bandwidth. 1920*1200* 18bit = 5 184 000 bytes. Then we could use Interlaced mode (flickerfixed ofcourse) and this will halve the bandwidth to 2 592 000 bytes. per frame. 2 592 000 bytes per frame in 50FPS(PAL) needs 126.5 MB per second and I think this is within Natami's capabilities. But the only person who can answer this correctly is Thomas.
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Thierry Atheist
Canada
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Posts 1828
24 Jan 2012 07:13
| I don't understand. Why not only do 25 FPS (PAL) and 30 FPS (NTSC) to have lower bandwidth needs? That's enough for smooth animation. Well, not that animation will be possible on a NatAmi at 1920*1080 or 1920*1200, for that matter. I accept that until an ASIC is made, that that is a limitation. NatAmi still RULES!!!!
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Rune Stensland
Norway
| | (MX-Board Owner)
Posts 871
24 Jan 2012 07:32
| PAL is actually 50Frames per second. but on tv the resolution is interlaced. First every odd scanline is updated, in the next frame every even scanline is updated. For smooth video 25fps is enough. For videogames 25 fps is perhaps not enough, but xbox users haven't complained.. HDTV has one or two million pixels per frame, roughly five times that of SD (1280 x 720 = 921,600 for 720p, or 1920 x 1080 = 2,073,600 for 1080p)
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Rune Stensland
Norway
| | (MX-Board Owner)
Posts 871
24 Jan 2012 07:43
| Marcel Verdaasdonk wrote:
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Thomas richer has recently been working on monitor drivers.
That i was refering to, it's fresh in memory.
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That is right we currenly have a monitor file that enables us to run Workbench smooth in 1280*1024 (not interlaced or dblpal).
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Nixus Minimax
Germany
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Posts 272
24 Jan 2012 10:15
| Rune Stensland wrote:
| | PAL is actually 50Frames per second. |
To be precise, PAL is 50 fields per second and 25 frames per second.
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Jakob Eriksson
Sweden
| | (Moderator)
Posts 1097
24 Jan 2012 10:46
| Unless in lo-res. :-) But maybe technically that is not PAL.
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Marcel Verdaasdonk
Netherlands
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Posts 3975
24 Jan 2012 13:32
| Neither is 1920*1200 nor 1080P
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Thomas Hirsch
Germany
| | (MX-Board Owner)
Posts 647
24 Jan 2012 14:31
| Natami uses currently a single channel DVI link. This limits the pixelclock to about 160MHz.
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Marcel Verdaasdonk
Netherlands
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Posts 3975
24 Jan 2012 16:14
| hm, 1920*1200*60=138.24MHz
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Claudio Wieland
Germany
| | (Natami Team)
Posts 703
24 Jan 2012 17:32
| Don't forget to account for sync signals and frontporch + backporch. It would be wise to respect official video formats, too ;-) .
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André Jernung
Sweden
| | (MX-Board Owner)
Posts 988
24 Jan 2012 19:50
| Marcel Verdaasdonk wrote:
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hm, 1920*1200*60=138.24MHz
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1920 X 1200 @ 60Hz has a total data rate of 193 MHz. This requires dual link DVI running at 96.5 MHz. But perhaps it could be solved with reduced blanking - such resolutions are not common on CRTs anyway.
Source: EXTERNAL LINK
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Marcel Verdaasdonk
Netherlands
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Posts 3975
24 Jan 2012 21:18
| André Jernung wrote:
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Marcel Verdaasdonk wrote:
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hm, 1920*1200*60=138.24MHz
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1920 X 1200 @ 60Hz has a total data rate of 193 MHz. This requires dual link DVI running at 96.5 MHz. But perhaps it could be solved with reduced blanking - such resolutions are not common on CRTs anyway.
Source: EXTERNAL LINK |
André according to your link 1080P also isn't available for the Natami. ;)
Besides i would like to know the math they used since it's about 1/3 higher then mine.
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Do you have questions about the Natami?